Thursday, November 13, 2014

DFDP-2 Calamity resolved! Mostly.

Rupert Sutherland, GNS Science and Victoria University of Wellington
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

A lovely morning at the site. 13/11/14. Photo R. Sutherland.

Successful fisherman, Richard. 
Photo: R. Sutherland 13/11/14
Yesterday, after it was clear that the drill had snapped and been left at the bottom of the hole (489 m depth), the drillers flew into action, quite literally. They went up to New Plymouth in their plane, obtained a fishing tool, got it back to our site, deployed it, attached to the lost drill, pulled it back to the surface, and took it apart. This was all complete by 4 a.m! It was an impressive effort.

The drill bit was damaged, but still in one piece. The bearings were broken. It was also badly worn, so must have been cutting a hole that was at least one cm too narrow. We think this explains the damage to the bottom stabiliser, but are still piecing together the facts.

Our next challenge is to check the integrity of all components and obtain new stabilisers. We hope to be drilling again very soon.

Everyone on site is now familiar with what a bottom-hole assembly (BHA) looks like. If you want to watch an explanation of the various parts and what they do, see our youtube video:

Comparison of broken drill bits. The bit recovered today (left) is badly worn and the bearings are loose. The bit dropped previously (right) has broken teeth and has cones jammed together. Photo R. Sutherland. 13/11/14.

Broken pin with stripped thread. This is the top of the recovered piece of BHA. Scratches visible at the top of the photo are from the fishing operation. 
Photo R. Sutherland 13/11/14.

Driller, Paul, is standing next to the fishing tool and a part of the recovered bottom section of the BHA. The drill collars beneath are part of the upper BHA. 
Photo R. Sutherland 13/11/14.
Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.